Bolt Maintenance Methods & Materials

Proper Cleaning and Lubrication Ensures Bolt Reliability and Long Life

by Germán A. Salazar, Contributing Editor

A good friend used to tell me she liked shooting bolt-action rifles because the only have one moving part: the bolt. This was a good laugh line back when we were shooting M1 and M14 service rifles with their multitude of moving parts and sub-assemblies. Of course, there’s a lot more that moves in a bolt-action than just the bolt, but it is the most important part or assembly of parts, so let’s take a look at the basics of bolt maintenance — even simple stuff needs your attention!

What you see in the first picture (top) is all that’s needed for the maintenance that should be performed each time the barrel is cleaned. Apart from the bolt itself, we have a jar of heavy, moly based grease from NECO (extreme pressure automotive axle grease will do), a small screwdriver to apply the grease, and a bolt take-down tool. There is no oil that will work as a bolt lubricant. Unlike AR15s which work with oil, a bolt-action rifle needs grease — ignore this warning at your own peril. The price of using oil will be an expensive gunsmith job to recut the galled lug seats and bolt lugs and then re-chamber the barrel for proper headspace.

Bolt Face, Ejector, Extractor

Grease, powder, and tiny brass particles can build up on your bolt face over time. It is wise to regularly clean your bolt face with a small, stiff, nylon brush and some light solvent such as Rem-Oil (which is mostly kerosene) or Eezox (good rust-preventer). After cleaning the face of the bolt, inspect the firing pin hole and clean it with a pipe-cleaner if necessary.

Next inspect the extractor and ejector. It’s not uncommon to find small brass particles and dried lube under the extractor hook. Clean that off. If you have a Sako-style extractor, pull the hook gently outwards (against spring pressure) to get better access. Next, clean off the ejector. If you can depress the ejector, remove any gunk or brass shavings around the plunger hole and clean the groove in the boltface where the ejector rides (white arrow in photo). Then ensure that the ejector functions properly. For a thorough cleaning, you should remove the ejector and spring — but you don’t need to do that very often with a bolt gun. However, if you have pierced primers recently, you should strip the bolt and clean out the ejector recess.

Firing Pin Assembly

You don’t really have to take the firing pin assembly out every time you clean the rifle, but it isn’t hard to do and you should have the tool in your kit. When misfires or blanked primers occur, the firing pin assembly should be removed and the inside of the bolt body flushed out. Gunk, congealed oil, bits of brass and primers, all sorts of things can accumulate in there and slow the firing pin’s fall. If you get caught in the rain during a match, disassembly and a coat of light oil on the spring for rust prevention is definitely called for.

Loosen the handle screw on the tool, slip the hook over the trigger catch on the firing pin and tighten the handle. The cocking piece will pull out of it’s notch and you then unscrew the firing pin assembly.

Note the white substance on the shroud threads, that’s common plumber’s teflon tape. Adding a couple of wraps to the threads tightens up the fit a little and keeps the shroud in good alignment with the firing pin as the pin releases and falls.

Flush out the interior with ordinary carburetor cleaner from the auto parts store. Re-wrap the shroud threads with teflon tape (optional) and re-assemble.

BOLT Lubrication

Like any piece of machinery subjected to high pressure and cyclical movement, the bolt needs lubrication. There are three main areas on a typical bolt that need lube: the locking lugs, the cocking cam, and the extraction cam.

1. The Rear Surface of the Locking Lugs

There are two lugs on most bolts, three or four lugs on some actions. Wipe these clean with a paper towel before re-applying the lube. Dab a little of the grease on the tip of the small screwdriver and spread it on the lugs. This should be a thin, even coat. Just thick enough to cover the metal but not globbed on. This picture shows the lugs wiped clean before lubing. A locking lug recess cleaning tool such as Sinclair Int’l offers is useful to ensure that any grit and bits of brass that collect in the receiver’s lug recesses get cleaned out.

2. The Cocking Cam

Look near the back of the bolt and you’ll see the cocking cam (sometimes called a cocking ramp). The cocking piece on the firing pin rides up the cam as you open the bolt and it needs lubrication. Wipe the old stuff off and apply a coat with the screwdriver blade. On some actions, like the RPA, this will be covered by the shroud – remove the shroud and lubricate – what you can’t see can hurt you!

3. The Extraction Cam

At the root of the bolt handle you’ll find the cocking cam. Look at the surface as well as the mating surface on the receiver and you’ll see how the cam creates a rearward movement of the bolt (primary extraction) as the bolt rotates open.

On some actions, the camming surface is on the receiver, on others it is on the bolt handle; either way, it needs to be lubed.

See that shiny spot on the cam? The timing of the extraction cam is not perfect on this action (as is often the case). In extreme cases, it might make extraction difficult, in mild cases, you might notice a click and a slight resistance at the top of the opening stroke.

So there you have it — basic bolt maintenance that you should be performing regularly to keep your rifle functioning trouble-free for as long as you keep screwing barrels on it. After all, with just one moving part, you really shouldn’t skimp on maintenance!